In the US today, more than 80,000 people - men, women, and children - live up to 23 hours a day in tiny cells without natural light, air, or human contact. Many remain there for months, years, or even decades.

The UN's expert on torture considers more than 15 days in solitary confinement a human rights violation. The US is the only democratic nation that makes widespread use of long-term solitary confinement in its prisons, even for minor, nonviolent infractions as simple as having too many postage stamps.

Is solitary confinement torture? What effect does it have on the people who endure it?

Five Mualimmak was in solitary confinement for five years of his 12-year sentence. He was kept in a windowless, gray concrete cell for violations as simple as having more than 7 pencils, which he used to draw portraits, or failing to finish his food. After 40,000 hours without any human contact, he lapsed into irrational rage and delirium, and permanently lost aspects of cognitive ability and any grasp of his personality—which only kept the infractions coming, adding to his indefinite stay in “the box.” Mualimmak was finally released from solitary and directly back onto the streets when his prison sentence ended.